Trim roses using sharp shears. Always cut them after 3 p.m., which is when the nutrient levels are high. If possible, leave at least three leaves on the stem, but remove any leaves that will fall below the eventual waterline of the vase.
Fill a bowl with hot (but not scalding) tap water. Add a floral preservative if desired, then add 1/4 teaspoon of bleach for every quart of water in the bowl.
Place the rose stems into the hot water mixture, then cut approximately 1/4 inch off the bottom of the stem. Be sure the buds do not touch the hot water. Allow the stems to sit in the water until the water returns to room temperature.
Add new warm water to a clean vase and then put in approximately two to three drops of bleach, along with a floral preservative.
Change the water whenever it appears cloudy, refilling the vase with hot water, a few drops of bleach and the floral preservative.